RSV and Flu Season: Protecting Your Baby Through the Winter
Two winter viruses, several new defenses. How the maternal RSV vaccine, infant antibodies, and the flu shot fit together to protect your baby.
RSV and Flu Season: Protecting Your Baby Through the Winter
Every fall, two respiratory viruses come for babies: RSV and influenza (flu). Both can be genuinely serious in the first year, and both are now largely preventable. Here's how the pieces fit together before the cold months hit.
RSV: new tools, big impact
RSV is a leading cause of hospitalization in US infants. The good news is that there are now two ways to protect a baby, and most babies need only one:
- A maternal RSV vaccine (Abrysvo) given during pregnancy, generally at 32–36 weeks in the fall or winter. Your antibodies cross to the baby and protect them for their first several months.
- An infant RSV antibody (such as nirsevimab) given to the baby directly — for those whose mothers didn't get the vaccine, or who enter their first RSV season unprotected.
In studies these sharply cut severe RSV, reducing RSV hospitalizations by roughly 80%. Timing matters: protection is aimed at the fall-through-winter season, when RSV typically peaks between December and January.
Flu: a yearly shot from 6 months
Everyone 6 months and older should get a flu vaccine every year, ideally in early fall. That leaves a gap: babies under 6 months are too young for the shot yet among the most vulnerable. Two things close it:
- Get a flu shot while pregnant — it passes protection to your newborn.
- "Cocoon" the baby by vaccinating everyone around them — parents, siblings, grandparents, caregivers.
Everyday defenses that still matter
Vaccines and antibodies do the heavy lifting, but the basics add up:
- Wash hands often, and ask visitors to do the same.
- Keep your baby away from anyone who's sick, and skip crowds during peak season if your baby is very young or premature.
- Keep your home smoke-free — secondhand smoke worsens respiratory illness.
- Breastfeeding, if you can, passes along some protection too.
When a cold is more than a cold
Most winter bugs are miserable but manageable. Call your pediatrician or seek urgent care if your baby has:
- Fast, hard, or labored breathing, or the skin pulling in around the ribs.
- Pauses in breathing, or a bluish tint to the lips or face (call 911).
- Signs of dehydration — far fewer wet diapers, no tears.
- Any fever in a baby under 3 months (always an urgent call).
RSV and flu protection shifts a little each season, and what your baby needs depends on their age, birth timing, and whether you were vaccinated in pregnancy. A quick conversation with your pediatrician before winter will sort out exactly which pieces your family needs.